Posted by George Washington - May 13, 2011 at 12:43 pm - Permalink - Source via Washington's Blog It is newsworthy that the operator of Japan's stricken nuclear plants is finally admitting that Fukushima reactor number 1 has melted down. But nuclear expert Arnie Gundersen says that the containment vessels for reactors 1, 2 and 3 are all leaking. However, Gundersen points out, the Nuclear Regulatory Commission assumes that containment vessels cannot leak and there is a "zero probability of containment leakage". U.S.. nuclear laws are based around that obviously false assumption.

Fukushima - One Step Forward and Four Steps Back as Each Unit Challenged by New Problems from Fairewinds Associates on Vimeo.

"TEPCO seems to be going backwards in getting the situation under control and things may well be slowly eroding with all the units having problems," said Tom Clements with Friends of the Earth, a U.S.-based environmental group. "At this point, TEPCO still finds itself in unchartered waters and is not able to carry out any plan to get the situation under control," he said.

As I discussed yesterday, Tepco has grossly mismanaged its response to the nuclear accident. The whole "douse the reactors" approach has failed miserably. Indeed, as the Guardian notes, flooding the reactors could cause new explosions:

Greenpeace has urged Tepco to abandon plans to flood the container with water, given the likelihood that melted fuel has damaged it. Shaun Burnie, nuclear adviser to Greenpeace Germany, said: "Flooding a reactor that has fuel [that has fallen] through the pressure vessel is not a good idea." Outlining a worst-case scenario, Burnie said very large amounts of cold water hitting the melted fuel could cause an explosion, trigger substantial damage to the reactor and create a "high risk of atmospheric release running for days, if not weeks." He added: "I think [the flooding option] will now be scrapped." *** "It seems to be poorly thought through," he said, adding that the firm had not demonstrated that the strategy could work.

There are various proposals for solving the Japanese nuclear crisis. As physicist Michio Kaku said only days after the accident:

What they are doing is basically using squirt guns against a raging forest fire. *** Do what Gorbachev did, call out the Japanese air force, get the army to bring a fleet of helicopters armed with sand, boric acid and concrete, entomb it, bury it in concrete.

As Reuters reports:

U.S. nuclear experts said that the company may have to build a concrete wall around the unit because of the breach, and that this could now take years. "If it is assumed the fuel did melt through the reactor, then the most likely solution is to encapsulate the entire unit. This may include constructing a concrete wall around the unit and building a protective cover over it," W. Gene Corley, senior vice president of CTL Group in Skokie, Illinois, said on Thursday. "Because of the high radiation that would be present if this has happened, the construction will take many months and may stretch into years," Corley said.

But since Fukushima is right on the Pacific Ocean, burying it in concrete would not necessarily stop leakage into the ocean. As Reuters reports, Gundersen might have a better - although technically difficult - approach:

TEPCO should consider digging a trench around reactors 1-3 all the way down to the bedrock, which is about 50 feet below the surface, said Arnie Gundersen, Chief Engineer at Fairewinds Associates Inc of Burlington, Vermont, who once worked on reactors of similar design to the Fukushima plant. He said this should be filled with zeolite, which can absorb radioactive cesium to stop more poisons from leaking into the groundwater around the plant.